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Wheelase Impact


SWharton

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This :

 

"The wheelbase-to-length ratio is the ratio of the length of the wheelbase (measured from the center of the front axle to the center of the rear axle) to the length of the motor home. We consider 54 percent as a minimum wheelbase-to-length ratio for safe highway travel. The categories for wheelbase-to-length ratio are as follows:

  • Excellent - 58% and above. Any wheelbase in this category should maintain a straight and steady course under most adverse driving conditions.
  • Good - 54%-57%.
  • Fatiguing - 51%-53% is considered fatiguing to drive because it will most probably not maintain a straight and steady course under normal highway driving conditions with side winds or heavy truck traffic.
  • Dangerous - 50% or below is considered dangerous at any speed on any road."

From : http://philip.greenspun.com/materialism/motorhomes/

 

Bounder = 52.777%

Winnebago = 56.018%

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Thank you for explaining the ratio. I had seen it mentioned but never an explanation and didn't go look for one. I looked at the specs for the Winnebago we are looking at and it works out to be 54%, the Bounder works out to be 52%. Seems like we are heading in the right direction.

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. I had seen it mentioned but never an explanation and didn't go look for one. I looked at the specs for the Winnebago we are looking at and it works out to be 54%, the Bounder works out to be 52%. Seems like we are heading in the right direction.

Let me add just a little bit to what was stated. I have driven a gas coach with a ratio of only 50% and then our second one had a ratio of 54% (seems to be a fairly common ratio). The difference isn't very noticeable under ideal driving conditions but when you get a side wind, or heavy truck traffic on a windy day, or even with heavy rain on the road, then that difference becomes a major factor! It was almost like driving a car with the higher ratio, even though the second coach was also 12' longer and heavier.

 

As you are considering the two, I suggest that you also compare the weight ratings of each because those can be just as important not only in what you carry but the distribution of that weight is just as important to handling as is the w-b ratio. You do not want a coach that has one side much heavier than the other. I have had that experience as well and it was an education.

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Unless I go to Smart Weigh I don't see how I would know the weight distribution. I am pretty sure(if MH follows the 5th wheels) that the heavy side by about 1000 lbs. will be the kitchen side. I don't see anyway around that problem. Any hints? The weight ratings seem to bethe same in the models we are looking at. Right now we are considering a 36' but are looking at the 32-34'. The big problem for us is so many have a 1/2 bath and we would rather have storage. WE have questions the dealer is we can drop the half bath and get storage instead. If we have road, wind, rain problems we just pull over for the night, we are never in a rush to get anyplace.

 

Making mods of this sort has not been a problem in our later 5th wheels(neither top of the line) but my impression is that MH mfgs. aren't very flexible.

 

We are currently leaning toward the Winnebago but need to see it in person once the snows melt. Also want to see it with all the slides in to see how the access is.

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If you are thinking of new then some motorhome manufacturers are willing to make at least some modifications to the plans but it does vary so be sure to ask. On the side to side information, I believe that Winnebago/Itasca is one of the companies who provide that information, or at least that they used to. You can do a lot to balance your RV when you load it by putting the heavy things on the lighter side. I kept my tools and such on the side away from the kitchen for example and located as nearly as possible to directly across from the refrigerator.

 

You can get axle weights from any truck scale and I strongly suggest doing so before you load the RV. If there are no barriers beside the chosen scale you can also get both sides by weighing once with all wheels on the scale and then a second time with the wheels of one side only on the scale, then just subtract to get what each side of each axle weighs.

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Thanks Kirk. We would certainly get weighed prior to loading. We have learned a lot as Escapees and weight/tires are 2 of the primary items.

 

On thing that surprised me is that a mfg like Newmar(we have looked at them and liked them) has only a 51-52% ratio. Now that I know about ratios(an educated consumer) I am not sure I want to persue the Newmar at all.

 

Any comments on this would be appreciated.

 

MY DW who has not liked a split bath has just said one would be OK, so we are basically at base 0 again as this brings in all sorts of floorplans that had been excluded. Good thing we are not in a rush.

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You can make suspension changes to compensate for a short wheelbase. Country Coach made a 32' diesel pusher with such changes and it drove quite well. Others have done so aftermarket. A well known place that makes these changes is Henderson's LineUp in Grants Pass, Oregon - http://www.hendersonslineup.com/.

 

SWharton: If the Newmar's have a tag axle, you can't use the normal wheelbase to calculate a ratio. For the ratio, use the the mid-point of the drive and tag axles for the rear.

 

http://www.rvforum.net/miscfiles/MH_Steering_Handling_%20Primer.pdf is a good primer on handling, suspensions and the changes you can make to improve handling.

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Thank you all for my education into MH. After spending several hours discussing the various floor plans we are back to the Winnebago, seems to give the most bang for the buck. I have emailed several dealers and only one has responded so far. Why they have email on their site and never respond is beyond my comprehension. I take tht to mean poor customer service even though they are rated well on rvservicereviews.com.

 

Does anyone know when the floor plans for the 2016 come out? We will need to sell our MDT and 5th prior to our special ordering the MH. We don't want to get caught between model years. Wish there was a way to have a sneekpeak of the 2016 floor plans though I doubt they will change much.

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Thank you all for my education into MH. After spending several hours discussing the various floor plans we are back to the Winnebago, seems to give the most bang for the buck. I have emailed several dealers and only one has responded so far. Why they have email on their site and never respond is beyond my comprehension. I take tht to mean poor customer service even though they are rated well on rvservicereviews.com.

 

Does anyone know when the floor plans for the 2016 come out? We will need to sell our MDT and 5th prior to our special ordering the MH. We don't want to get caught between model years. Wish there was a way to have a sneekpeak of the 2016 floor plans though I doubt they will change much.

I have noticed that if a floor plan has been in use for a few or several years, it may be suddenly discontinued for the next model year. We buy used RV's and have looked at particular floor plans in the Winnebago archive brochures. They seem to keep the same floor plan for several years and then change. I guess if the model stops selling well, they change it.

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In my MH the refrig. is on the passenger side and the rest of the kitchen is on the driver side. Which side will be heavier?

The type of tires can make a difference in how the MH handles. I have seen some MHs with 16 inch tires that would not handle well at all due to tire flex. One step up to 19.5 tires and all is great, the tires are lower profile and all steel construction, they handle much better.

 

You have to look at the whole package and buy what works.

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We are settling on the Winnebago(unless something changes). One reason is it has 22.5 tires which are easily findable,not sure about the 19.5 tires. We have found on our MDT that the Toyo tires work well, need to see what brand is on the MH, if they are some chinese junk tires we will switch them out ASAP. Coming from the 5th wheel side some things are the same and some are different. WE are gettinginformation on what we consider the "different".

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We are settling on the Winnebago(unless something changes). One reason is it has 22.5 tires which are easily findable,not sure about the 19.5 tires.

Since all class A gas coaches today are built on the Ford chassis, are you sure that they do not also all have the 22.5 tire? I thought that all Ford chassis now use the 22.5" tires and you are probably looking at the same chassis on either coach, unless it is a different GVWR and/or wheel base. Since you plan to special order, I'd think that chassis could be the same on either one and I would lean to the higher GVWR & wheel base?

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I think the break over weight on the Ford Chassis is around 20-22K pounds. I am pretty sure the 18K # and lower has 19.5" wheels and the 22K # and above have 22.5" wheels. My 2006 18K GVWR has 19.5" & when I was looking at the 22.5K I saw they had 22.5".

 

I don't think the Ford F53 Chassis (the chassis they build the class A's on) comes with anything smaller than 19.5" wheels. Many or maybe all the Van cutaway chassis the class C's are built on come with 16" wheels.

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Based on all my reading is the Winnebago comes with 19.5 but you can get 22.5. Looking at MSRP the 22.5 is NC and I haven't seen any without the 22.5. Don't know where the break point is but we are looking at the 36Y(mainly because everything elese has 1 1/2 baths and we would rather have the storage). We are checking into deleting the 1/2 bath and getting a storage closet. No answer on that yet.

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I just found the 2014 Ford listing of chassis specs and it seems that they do still use the 19.5" tires on the 18k & 20.5K chassis and 19.5" with optional 22" on the 22K chassis. The 24K & 26K chassis come only with the 22" tire. So it would depend upon the coach builder which tire comes on a class A that is built on the 22K, GVWR Ford chassis and if on either of the lower rated ones it will be the 19.5" tire only.

 

Must be that I was only looking at the coaches with the hirer rated chassis when we went to the last show.... I really don't think that you would find the 19.5 tires difficult to find, at least we never did. I still prefer the 22" tires but the coach that we had rode on the 19.5" tires and while not every shop has them in stock, it was never a problem for us.

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I just found the 2014 Ford listing of chassis specs and it seems that they do still use the 19.5" tires on the 18k & 20.5K chassis and 19.5" with optional 22" on the 22K chassis. The 24K & 26K chassis come only with the 22" tire. So it would depend upon the coach builder which tire comes on a class A that is built on the 22K, GVWR Ford chassis and if on either of the lower rated ones it will be the 19.5" tire only.

 

Must be that I was only looking at the coaches with the hirer rated chassis when we went to the last show.... I really don't think that you would find the 19.5 tires difficult to find, at least we never did. I still prefer the 22" tires but the coach that we had rode on the 19.5" tires and while not every shop has them in stock, it was never a problem for us.

 

A lot of tire shops can get which ever tires you choose in a days time .

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